Do you remember Schrödinger's cat, simultaneously alive and dead? Well, now we have something even stranger to tell you. The excitons, quantum particles that already have bizarre behaviors, have just shown properties that defy all known categorization. It's as if we've discovered a new species of particle that doesn't follow the rules we thought were universal.
What are Excitons, Simply Explained
An exciton is a physical phenomenon that occurs when a material absorbs energy, typically in the form of light. In simple terms, it is a pair of an electron and a “hole” (the empty space left by the electron), which remain bound together by an electrical force. When light strikes a semiconductor or insulator material, an electron is knocked out of its normal position, leaving behind an empty space. The electron and hole, although separate, remain somewhat connected, as if they were joined by an invisible rubber band. This pair can move through the material, carrying energy.
Excitons are temporary states: sooner or later the electron will return to its original position, reuniting with the hole. When this happens, energy is released in the form of light. This process is fundamental to the functioning of many modern technologies, from LEDs to solar cells, where the management of excitons is crucial to the efficiency of the devices.
The discovery that defies the rules
The team of Brown University did something really ingenious. The researchers created a structure using two layers of graphene (the dreaded, much-maligned graphene, a two-dimensional material as thick as an atom) separated by an insulating crystal of hexagonal boron nitride.
Most excitingly, this discovery opens the door to a new frontier for future research, deepening our understanding of fundamental physics and opening up new possibilities in the field of quantum computing.
Jia li, associate professor of physics at Brown University.
Excitons, a Rebel “Quantum Behavior”
The excitons observed by the team turned out to be real rebels of the quantum world. Generally, particles fall into two main categories: bosons, who love to be together in the same quantum state, and Fermions, who prefer to keep their distance. But these new fractional excitons do not seem to want to respect these rules, behaving a bit like one and a bit like the other.
Secondo Naiyuan Zhang, lead author of the study published in Nature (that I link to you here), this discovery could have revolutionary implications for the future of quantum computing. Fractional excitons could be used to store and manipulate information in entirely new ways, dramatically increasing the speed and reliability of quantum computers.
A new frontier to explore
D.E. Feldman, co-author of the study, expressed his enthusiasm very vividly:
It's as if we have our finger right on the knob of quantum mechanics. It's an aspect of quantum mechanics that we didn't know about or, at least, didn't appreciate before now.
The team is already planning further studies to better understand how these particular excitons interact with each other and how we can effectively control them. What can I say: exciting news (bear with me).
